Native to the southern Mediterranean, the bay laurel (Laurus nobilis) produces fragrant dark green leaves that contain an essential oil used to flavor culinary dishes. The oil of the sharped-edged, ovate leaves may cause irritation in some individuals, so use caution when planting or working with a bay laurel. This evergreen plant grows as a small tree or large shrub in U.S. Department of Agriculture plant hardiness zones 8 through 11. Although the bay laurel grows slowly, without annual pruning and shaping, it will become overgrown. Cut your unkempt bay laurel back to size using proper pruning techniques in the late winter while it remains dormant.
Pour 1 part 70 percent isopropyl alcohol and 1 part water into a small bucket. Swirl the liquids together. Place the blades of pruning shears and loppers into the solution. Let the tools soak for five minutes. Let the blades air dry before making any cuts.
Put on a long-sleeved shirt and gloves to protect your hands and arms from direct contact with the bay laurel's foliage. Keep your skin covered fully when working with the plant to prevent cuts and irritation from occurring.
Examine the bay laurel, looking for dry, leafless or light gray branches. Scrape a 1/4-inch-long section of the bark from each of these branches to confirm their lack of green wood, a sign of death. Cut the branch from the plant if the tissue underneath the bark appears white, brown or gray without any green. Make each cut 1/4 inch above the branch's swollen ring of bark surrounding its base. Use pruning shears to cut through branches with a diameter of 1/4 inch or less, and pruning shears for branches greater than 1/4 inch.
Cut back any broken branches to at least 1 inch below the damaged portion. Make the cut 1/4 inch above an outward-facing leaf bud, side shoot or branch base.
Prune away any limbs that cross or rub against others. Remove one or two branches in crowded sections to thin the canopy and allow light in. Remove the oldest limbs first when thinning out portions of the bay laurel.
Cut all suckers arising from the bay laurel's trunk back to 1/4 inch above the trunk. Avoid cutting into or damaging the trunk. Remove all suckers growing from the ground surrounding the plant, cutting them back to ground level.
Prune back the tips of the remaining branches by one-third to shape the plant into a defined rounded or pyramidal habit. Make each of these heading cuts 1/4 inch above an outward-facing lateral branch or bud to encourage outward branching.
Cut the removed limbs into smaller 3 to 6 inches pieces with the loppers or pruning shears. Discard the plant material in a trash bin. Rake up any fallen leaves or small twigs around the bay laurel's base. Discard the leaves and twigs in the trash bin. Sterilize the tools in the same manner as before once you finish making cuts to eradicate any clinging pathogens.
Check the bay laurel plant one to two months later after new active growth begins. Trim out any watersprouts, or thin vertical shoots, growing from or near the pruning cuts. If left to grow, these shoots will create weak growth and shade in the bay laurel's canopy.